package com.warmheart.core.util;

/**
 * 
 * @ClassName: DistanceUtil
 * @Description: 通过经纬度计算两点之间的距离
 * @author hqkj
 * @date 2025-06-16 09:37:02
 *
 */
public class DistanceUtil {

    private static double EARTH_RADIUS = 6378.137;

    /**
     * 通过经纬度获取距离(单位：米)
     * 
     * @param lat1
     * @param lng1
     * @param lat2
     * @param lng2
     * @return
     */
    public static double getDistance(double lat1, double lng1, double lat2, double lng2) {
        double radLat1 = rad(lat1);
        double radLat2 = rad(lat2);
        double a = radLat1 - radLat2;
        double b = rad(lng1) - rad(lng2);
        double s = 2 * Math.asin(Math.sqrt(
                Math.pow(Math.sin(a / 2), 2) + Math.cos(radLat1) * Math.cos(radLat2) * Math.pow(Math.sin(b / 2), 2)));
        s = s * EARTH_RADIUS;
        s = Math.round(s * 10000d) / 10000d;
        s = s * 1000;
        return s;
    }

    private static double rad(double d) {
        return d * Math.PI / 180.0;
    }

    public static void main(String[] args) {
        System.out.println(getDistance(31.802656, 117.34917, 31.8583, 117.21462));
        System.out.println(getDistance(31.802656, 117.34917, 39.89975, 116.48241));
    }

}
